The option to enable SharePlay on HomePod has been removed from tvOS and iOS 17.4 beta software.
Apple has pulled the SharePlay feature on HomePod operating system, presumably after testing was done in tvOS 17.4 and iOS 17.4 beta. Developers noted that it was gone in the second beta iteration where it appeared in the first beta. SharePlay functionality allows users to use apps, listen to music, play games, and watch TV over FaceTime. Apple is steadily adding more options, such as contributing to a shared playlist in CarPlay.
The SharePlay feature works by scanning a QR code on the screen for access. For Apple TV and HomePod owners, a subscription to Apple Music is required with the exception of those who are contributing to a playlist. At this point, it’s not clear whether Apple will put back SharePlay or will have it introduced in official 17.4 versions.